rust-clippy/tests/ui/result_map_unit_fn.rs
Mateusz Mikuła cc7d66aa9c rustup
2018-04-27 14:00:43 +02:00

103 lines
2.6 KiB
Rust

#![feature(never_type)]
#![warn(result_map_unit_fn)]
#![allow(unused)]
fn do_nothing<T>(_: T) {}
fn diverge<T>(_: T) -> ! {
panic!()
}
fn plus_one(value: usize) -> usize {
value + 1
}
struct HasResult {
field: Result<usize, usize>,
}
impl HasResult {
fn do_result_nothing(self: &Self, value: usize) {}
fn do_result_plus_one(self: &Self, value: usize) -> usize {
value + 1
}
}
fn result_map_unit_fn() {
let x = HasResult { field: Ok(10) };
x.field.map(plus_one);
let _ : Result<(), usize> = x.field.map(do_nothing);
x.field.map(do_nothing);
x.field.map(do_nothing);
x.field.map(diverge);
let captured = 10;
if let Ok(value) = x.field { do_nothing(value + captured) };
let _ : Result<(), usize> = x.field.map(|value| do_nothing(value + captured));
x.field.map(|value| x.do_result_nothing(value + captured));
x.field.map(|value| { x.do_result_plus_one(value + captured); });
x.field.map(|value| do_nothing(value + captured));
x.field.map(|value| { do_nothing(value + captured) });
x.field.map(|value| { do_nothing(value + captured); });
x.field.map(|value| { { do_nothing(value + captured); } });
x.field.map(|value| diverge(value + captured));
x.field.map(|value| { diverge(value + captured) });
x.field.map(|value| { diverge(value + captured); });
x.field.map(|value| { { diverge(value + captured); } });
x.field.map(|value| plus_one(value + captured));
x.field.map(|value| { plus_one(value + captured) });
x.field.map(|value| { let y = plus_one(value + captured); });
x.field.map(|value| { plus_one(value + captured); });
x.field.map(|value| { { plus_one(value + captured); } });
x.field.map(|ref value| { do_nothing(value + captured) });
x.field.map(|value| { do_nothing(value); do_nothing(value) });
x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
// Suggestion for the let block should be `{ ... }` as it's too difficult to build a
// proper suggestion for these cases
x.field.map(|value| {
do_nothing(value);
do_nothing(value)
});
x.field.map(|value| { do_nothing(value); do_nothing(value); });
// The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let variable name for them
let res: Result<!, usize> = Ok(42).map(diverge);
"12".parse::<i32>().map(diverge);
let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
// Should suggest `if let Ok(_y) ...` to not override the existing foo variable
let y: Result<usize, usize> = Ok(42);
y.map(do_nothing);
}
fn main() {
}